The Journal of surgical research
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In the tumor-bearing host, depression of cell-mediated immunity has been well-demonstrated, but little is known about alterations in macrophage functions. We hypothesized that the presence of a tumor may cause functional suppression of peritoneal macrophage and splenic macrophage functions, perhaps due to prostaglandin-E2 (PGE2) and nitric oxide. C57 BL/6 mice (n = 18) were injected subcutaneously with Lewis lung carcinoma 3 tumor. ⋯ In the tumor-bearing host, peritoneal macrophages have significantly decreased accessory and effector functions. Splenic macrophages demonstrate decreased accessory but enhanced effector functions. PGE2, superoxide, and nitric oxide appear to be important mechanisms of altered macrophage function in the tumor-bearing host; modifying their cellular production may enhance host defense.
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To determine the influence of insulin-like growth factor-1 (IGF-1) on nitrogen loss and hepatic response to critical illness, 34 male Sprague-Dawley rats (190-230 g) were randomized to receive parenteral nutrition (PN) only (Ctrl), PN plus continuous infusion of Escherichia coli 026:B6 lipopolysaccharide at 6 mg/kg/day (LPS), or PN plus LPS plus rhIGF-1 (IGF-1) at 3 mg/kg/day for 48 hr. Prior to randomization, all animals underwent iv cannulation and 30 hr of adaptation to PN. All animals received isocaloric and isonitrogenous PN (glucose 170 kcal/kg/day and nitrogen 1.1 g/kg/day) and were kept NPO except for water ad libitum. [15N]glycine was infused in all animals for determination of liver fractional synthetic rate. ⋯ Endotoxin significantly increased the urinary 3-methylhistidine/creatinine ratio (0.24 +/- 0.05, 0.55 +/- 0.12, 0.48 +/- 0.17 for the Ctrl, LPS, and IGF-1 groups, respectively; ANOVA, P < 0.001); however, IGF-1 did not significantly reduce the ratio. Endotoxin induced a significant increase in liver fractional synthetic rate (29 +/- 8, 56 +/- 18, 64 +/- 12%/day for the Ctrl, LPS, and IGF-1 groups, respectively; ANOVA, P < 0.01) and depressed hepatic cytochrome P450 concentration (0.54 +/- 0.19, 0.22 +/- 0.07, 0.19 +/- 0.07 nmol/mg protein, respectively; ANOVA, P < 0.05) and ethoxycoumarin O-deethylase (ECOD) activity (103 +/- 73, 29 +/- 13, 17 +/- 11, pmol/mg/min, respectively; ANOVA, P < 0.01); however, rhIGF-1 did not significantly alter these hepatic variables during endotoxin infusion. Recombinant human insulin-like growth factor-1 significantly improved nitrogen balance without compromising hepatic response as measured by liver fractional synthetic rate, cytochrome P450 concentration, and ECOD activity in endotoxemic parenterally fed rats.
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Comparative Study
Comparison of the hemodynamic effects of gasless abdominal distention and CO2 pneumoperitoneum during incremental positive end-expiratory pressure.
Laparoscopy is used increasingly in managing critically ill patients. Carbon dioxide (CO2) pneumoperitoneum is used during these procedures. The increased intra-abdominal pressure of CO2 pneumoperitoneum, however, can affect cardiopulmonary performance adversely. ⋯ With GAD, central venous pressure (CVP), pulmonary artery pressure (PAP), pulmonary capillary wedge pressure (PCWP), and PaCO2 were significantly reduced, compared to PNEUMO, and PaO2 was increased. Cardiac index was higher in GAD versus PNEUMO at baseline, but was lower for GAD at PEEP levels above 10 cm H2O. These results indicate that in its net effect, GAD does not exacerbate the adverse hemodynamic effects of PEEP.(ABSTRACT TRUNCATED AT 250 WORDS)
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Techniques for determining intraoperative compromise in colonic blood flow during aortic reconstruction are inadequate. We investigated the use of transanally recorded oxygen saturation in a porcine model. A Nellcor RS-10 reflectance pulse oximeter probe was attached to the balloon of a Foley catheter and passed transanally to record the oxygen saturation of the sigmoid colonic mucosa. ⋯ At 20% of basal CMA flow, colonic O2 saturation was 54.0% +/- 4.1. Below 20% of basal CMA flow there was an abrupt loss of signal from the pulse oximeter. This study suggests that transanal pulse oximetry would provide a simple means of continuously monitoring the adequacy of distal colonic blood flow intraoperatively and may prove to be useful during aortic reconstruction when there is concern about the adequacy of blood flow to the distal colon.
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Organ transplantation in presensitized recipients continues to be contraindicated for heart and kidney recipients due to the risk of hyperacute rejection, which has no known treatment at this time. We tested whether donor serum, which contains soluble MHC class I antigen, is able to neutralize the effect of anti-donor antibody in the recipient and prevent hyperacute or accelerated rejection. A rat model of passive immunization was used to test the role of anti-donor antibody in hyperacute rejection. ⋯ However, removal of RT1. Aa antigen from ACI serum prior to use in the passive transfer model did not abrogate the graft prolongation observed previously. These data suggest that components of donor serum other than MHC class I antigen may be useful for preventing the antibody-mediated component of hyperacute rejection.